Slant Six overheat at cruise speed, especially going uphill

feel the radiator after your up to temp. If there are colder spots, your gummed up. A rod out is still an option even in your neck of the jungle.

got pools in Malaysia? Try this pool acid procedure on some dirt lot, itll etch concrete and kill grass...
"...For about $1 worth of solution, you can clean it as well as any radiator shop, especially since you will have to remove it anyway, unless you want to pay a highly trained radiator "technician" and add that to the bill.

The radiator flush article in Toyota Trails, as referenced above, was written by Mark Whatley and is on page 25 of the July/August 1998 issue. To summarize:
..remove the radiator or heater core
..empty the remaining coolant
..position the openings facing up and fill with muriatic acid. Let it sit for 10 - 15 minutes--no more
..flush with clean water, and repeat the procedure.
..flush thoroughly with clean water, and re-install

Three things: this procedure is designed for old-fashioned, brass radiators. Never use on the new-style aluminum/plastic coolers. Do not use the acid wash with the radiator in the vehicle--it will inevitably spill on surrounding parts and damage them. Finally, don't spill this mess on your driveway. It will eat concrete...."


I would add a baking soda water final rinse to neutralize any residual acid. Works on heater cores too. CLR is also good, but more expensive.